Josh McCown is perhaps the most well-traveled active player in the NFL. In his 15 seasons, he’s seen regular-season action for six different teams. That’s not counting 2006, when he spent the whole campaign as the Lions’ backup. And he was on the training camp roster of an additional two teams — the Dolphins in 2008 and the 49ers in 2011.

So the 38-year-old Jets quarterback understands better than most the difficulty of learning new offenses, and he can relate to Christian Hackenberg, who is being forced to learn an entirely new system in his second season after the Jets moved on from OC Chan Gailey and replaced him with John Morton.

“I think it’s very hard,” McCown said Friday in Florham Park, where Jets players reported for training camp. “You want to know the terminology because when you’re walking to the line of scrimmage as a quarterback and as you grow as a player, you don’t want to be thinking about, what do we call this formation this year? Or what do we call this play this year? You want to be thinking about your footwork, the defense, just different things to where you can hone your skills and get better at it.”

Christian Hackenberg is being forced to learn an entirely new system in his second season.

McCown enters training camp locked in a starting quarterback battle with Hackenberg and Bryce Petty. He embraces the role as mentor for the two youngsters but he has every intention of winning the starting job.

It’s a delicate balance for McCown, who draws on his experience coaching high school football for two seasons while out of the NFL in 2011 and 2012 to help him connect with younger players.

Bryce Petty.

(Julio Cortez/AP)

“This has been an unbelievable journey, and sure, would I have wanted it to be with one team and have one of those careers? Absolutely,” McCown said. “But I’m still very thankful for it, and I want other guys to be able to have that opportunity.”

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Guard Brian Winters — who underwent shoulder surgery this offseason and signed a four-year contract extension in January — said he doesn’t expect any limitations during training camp.

Tackle Ben Ijalana (knee scope) said he will “be a little limited” during the early stages of camp. He underwent the operation seven weeks ago. Ijalana will compete with Kelvin Beachum at left tackle.